** Stone Retaining Walls ** Back in their day Railroad Tie retaining walls were the only way to go when you needed a wall in your landscape. For the last 12-14 years Stone Retaining Walls has taken the landscape industry by storm. And for good reason, stone walls are built to last a lifetime. No rotting, no sagging after years of weather, availibility in many colors, shapes, and textures. T.C.Outdoor installs the Keystone Retaining Wall System and Versalok Retaining Wall System. Both are available in various colors, sizes, and shapes. These types of retaining walls require no Mortar and utilize an interlocking pin design for years of durability.